Cosmological implications of the first year W ILKINSON M ICROWAVE A NISOTROPY P ROBE results Licia Verde University of Pennsylvania

David Wilkinson

NASA/GSFC Chuck Bennett (PI) Michael Greason Bob Hill Gary Hinshaw Al Kogut Michele Limon Nils Odegard Janet Weiland Ed Wollack Princeton Chris Barnes Norm Jarosik Eiichiro Komatsu Michael Nolta UBC Mark Halpern Chicago Stephan Meyer Brown Greg Tucker UCLA Ned Wright Science Team: WMAP A partnership between NASA/GSFC and Princeton Lyman Page Hiranya Peiris David Spergel Licia Verde

(Most of) WMAP Science Team, August 2002

Launched from cape Canaveral on June

Trajectory 100 days to L2, 1.5e6 km from Earth. Lunar swingby Phasing loops Official arrival date: Oct 1, 2001

MAP Big Bang TIME TEMP. Inflation-like epoch. Cosmic History CMB decouples from plasma First stars form NOW new

HOW? WHY? “Seeing sound” (W. Hu) Last scattering surface : snapshot of the photon-baryon fluid Photons radiation pressure Gravity compression On large scales : primordial ripples What put them there? On smaller scales: Sound waves Horizon size at LSS  Fundamental mode (over tones) Stop oscillating at recombination { } CMB THEORY

Some history

Meanwhile,on the other side of the iron curtain…

Bennett et al 2003 COBE 1992 WMAP 2003

If the anisotropy is a Gaussian random field all the statistical information is contained in the angular power spectrum (real and imaginary parts of each independent normal deviates, not correlated.) Raw 94 GHz near NEP Raw 61 GHz near NEP +/- 32 uK Express sky as: 5 deg 0.06% of map X 1 deg Compress the CMB map to study cosmology

Before 11 Feb (From Hinshaw et al 2003)

After Why only? (Komatsu et al. 2003)

Primordial ripples Fundamental mode 1 deg compression rarefaction compression Acoustic peaks

Primordial ripples Fundamental mode Geometry Potential wells compression baryons Rarefaction… etc

From Wayne Hu Polarization of the CMB is produced by Thompson scattering of a quadrupolar radiation pattern. At decoupling, the quadrupole is produced by velocity gradients. A component of the polarization is correlated with the temperature anisotropy. Coulson et al 2 deg Cold spot Hot spot POLARIZATION EFFECT #1: CONFIRMATION OF PHYSICAL ASSUMPTIONS.

Generation of CMB polarization Temperature quadrupole at the surface of last scatter generates polarization.

Temperature-polarization correlation Radial (tangential) pattern around cold (hot) spots.

POLARIZATION EFFECT #2: REIONIZATION BY FIRST OBJECTS. Stars form near z~20, light reionizes the plasma. Free electrons scatter CMB photons, uniformly suppressing the fluctuations by 30% for l>40. Free electrons see the local z~20 CMB quadrupole and polarize the CMB at large angular scales, where no other mechanism of polarization operates. Based on Tegmark Conformal spacetime diagram with one spatial dimension not shown.

Large Scale TE anti-correlation WMAP TE data in bins of Δl=10 Primordial Adiabatic i.c. Causal Seed model (Durrer et al. 2002) Primordial Isocurvature i.c. Kogut et al (2003) Peiris et al. 2003

(Kogut et al. 2003) TE cross-correlation Prediction from TT spectrum The TT spectrum makes precise predictions for the TE spectrum We saw it. Triumph for the standard cosmological model.

The angular power spectrum is a function of ~15 cosmological parameters. Perturbations are linear. Select parameters Compute model with CMBFAST Compare to measured, find L Repeat to find confidence regions. The simplest best fit model has 6 parameters and Interpretation: The analysis path follows: Lineweaver e.g., Kosowsky et al. Christensen et al. Selkak & Zaldarriaga The probability to exceed is 5% Can combine data with external surveys as well. Sachs&Wolfe 1967 Silk 1968 Peebles & Yu 1970 Sunyaev & Zel’dovich 1970

RESULTS: WMAP only (TT+TE), flat LCDM 15% of CMB was re-scattered in a reionized universe. The estimated reionization redshift ~20, or 200 million years after the Big-Bang. Flat LCDM still fits: 6 parameters fit 1348 points Fits not only the CMB but also a host of other cosmological observations. CMB appears to be Gaussian. marginalized (Spergel et al. 2003) AgeGyr atomic density Age at decoupling DM densityKg/m 3 (Komatsu et al.)

WMAP only (TT+TE), flat LCDM RESULTS: TE alone: marginalized degeneracy (Spergel et al. 2003) (Kogut et al 2003)

WMAP only: degeneracies Main degeneracy joint confidence contours 1 and 2 (TT+TE) Will get better soon

CBIACBAR Lyman alpha forest TEST MODEL CONSISTENCY and LIFT DEGENERACiES WMAPext Complementary in scales and redshift

BEYOND LCDM modelFLATNESS de Bernardis et al 2000 (Spergel et al 2003) Riess et al Verde et al 2002 After + HST meas. of Ho

We (and all of chemistry) are a small minority in the Universe.

CONSTRAINTS ON NEUTRINO MASS P(K) amplitude Factor of few better than previous cosmological constraints (Elgaroey et al.2002)

Quintessence

Running spectral index: This is our “best fit” model Can add tensors and get limits on r (Peiris et al. 2003) Parameters do not shift when adding other data sets.(all data) suggestion WMAP power law

INTRIGUING … l l Cl

Conclusions: Boring LCDM universe with a twist: the universe was reionized at We have extrapolated forwards the observations. The model seems to work so well that we can attempt to extrapolate it backwards, before (Peiris et al. 2003) Constraints on inflation! We have a standard cosmological model : 6 (or 7) parameters fit all. For physicists For astronomers Data, software, papers and results are at:

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